Search found 34 matches

by Tobie Jessup Section 3D
Sun Nov 22, 2020 12:01 pm
Forum: Ionic & Covalent Bonds
Topic: Polar/ Nonpolar
Replies: 21
Views: 83

Re: Polar/ Nonpolar

Its been easiest for me to compare the electronegatvities of the atoms to determine in the molecule is polar, but shape is also an indicator as to whether or not an atom is polar.
by Tobie Jessup Section 3D
Sun Nov 22, 2020 11:59 am
Forum: Bond Lengths & Energies
Topic: Bond Strength in DNA
Replies: 12
Views: 50

Re: Bond Strength in DNA

The strength of intermolecular interactions increase with the number of individual interactions/bonds, so the 3 hydrogen bonds in G-C bonding makes them strong than A-T bonding which only has 2 hydrogen bonds.
by Tobie Jessup Section 3D
Sun Nov 22, 2020 11:56 am
Forum: Bond Lengths & Energies
Topic: IMF vs. Intramolecular Forces
Replies: 7
Views: 50

Re: IMF vs. Intramolecular Forces

I also believe that the question is asking about intramolecular forces based on the language of the question. If the question was wanting to test the students knowledge on IMFs I think there would be specific language about LDFs or other intermolecular forces. The question is most likely questioning...
by Tobie Jessup Section 3D
Sun Nov 22, 2020 11:52 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Sampling 4
Replies: 4
Views: 30

Re: Sampling 4

You should think about how a square pyramidal shape could be formed from any of the basic shapes by removing bonding pairs and replacing them with lone pairs. For instance, you can form a square pyramidal shape by taking an tetrahedral shape and removing any one of the bonding pairs and replacing i...
by Tobie Jessup Section 3D
Sun Nov 22, 2020 11:51 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Repulsion Strength
Replies: 8
Views: 29

Re: Repulsion Strength

From one of Dr. Lavelle's lectures, I remember him ranking repulsion strength as so: lone pair-lone pair> lone pair-bonding pair> bonding pair bonding pair.
by Tobie Jessup Section 3D
Sun Nov 15, 2020 1:17 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Sapling Weeks 5-6 #9
Replies: 3
Views: 39

Re: Sapling Weeks 5-6 #9

You pretty much just have to memorize the rules for oxidation numbers. Oxygen always has an oxidation number of -2, except in peroxides and F2O. If you add up the -2 charges of all 4 oxygens, you get -8. In order for the charge of the overall molecule to be -1, Cl must have an oxidation number of +...
by Tobie Jessup Section 3D
Sun Nov 15, 2020 1:15 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Oxidation Number
Replies: 8
Views: 57

Re: Oxidation Number

When I took chemistry in high school, I had to memorize the oxidation numbers. Group1 is +1, Group2 is +2, Fluorine is -1, Group15 is -1, Group16 is -2, Group17 is -3, Oxygen is usually -2(not when with fluorine or peroxides), Hydrogen is +1 when paired with non-metals and -1 when paired with metal...
by Tobie Jessup Section 3D
Sun Nov 15, 2020 1:14 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge vs Octet Rule
Replies: 12
Views: 203

Re: Formal Charge vs Octet Rule

Use the octet rule to first determine lewis structure but the lowest formal charge is used to determine which is most stable between difference resonance structures.
by Tobie Jessup Section 3D
Sun Nov 15, 2020 1:09 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Helpful screenshot of oxidation rules from textbook
Replies: 7
Views: 45

Re: Helpful screenshot of oxidation rules from textbook

This is super helpful I've been having trouble with these, thanks!
by Tobie Jessup Section 3D
Sun Nov 15, 2020 1:08 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Number of Resonance Structures
Replies: 7
Views: 46

Re: Number of Resonance Structures

Hi! From my understanding, there's no easy way to know or calculate how many resonance structures there are for a molecule, you just have to practice knowing how to identify them when drawing the Lewis structure. Hopefully, we will be given relatively simple ones if asked on the midterm, like C4H4,...
by Tobie Jessup Section 3D
Sun Nov 08, 2020 9:32 pm
Forum: Coordinate Covalent Bonds
Topic: Just to clear it up
Replies: 13
Views: 213

Re: Just to clear it up

The Lewis base donates the electrons in coordinate covalent bonds, but Lewis bases don't solely create coordinate covalent bonds.
by Tobie Jessup Section 3D
Sun Nov 08, 2020 9:30 pm
Forum: Ionic & Covalent Bonds
Topic: Atomic Radius
Replies: 38
Views: 143

Re: Atomic Radius

As your move across the periodic table, more protons are added to the nucleus and therefore there is a stronger positive charge that pulls the electrons closer to the nucleus.
by Tobie Jessup Section 3D
Sun Nov 08, 2020 9:25 pm
Forum: Ionic & Covalent Bonds
Topic: formal charge
Replies: 8
Views: 35

Re: formal charge

I am also a bit confused with formal charge. To my understanding, I know that calculating the FC of single atoms is important when checking the stability of a molecule because rearranging bonds to have atoms with FCs of zero creates a more table structure overall. Hopefully that was a bit helpful!
by Tobie Jessup Section 3D
Sun Nov 08, 2020 9:18 pm
Forum: Lewis Structures
Topic: octet rule
Replies: 7
Views: 47

Re: octet rule

The three examples of violations to the octet rule we have talked about in class so far are electron-deficient molecules, radicals, and elements with an expanded octet. Typical electron-deficient elements, like Boron and Aluminum (Group 13 elements) with 3 valence electrons would need to gain an ad...
by Tobie Jessup Section 3D
Sun Nov 01, 2020 11:00 pm
Forum: Properties of Electrons
Topic: Electron Spin
Replies: 7
Views: 48

Re: Electron Spin

We say that the first electron spins up, but that value doesn't mean much since the positive and negative directions don't have meaning. I know that 2 electrons in the same sub shell do not spin the same direction.
by Tobie Jessup Section 3D
Sun Nov 01, 2020 10:58 pm
Forum: Properties of Electrons
Topic: Sapling #11
Replies: 6
Views: 66

Re: Sapling #11

l values correspond to s, p, d, and f quantum numbers so l=0 is s, l=1 is p, l=2 is d, l=3 is f.
by Tobie Jessup Section 3D
Sun Nov 01, 2020 10:57 pm
Forum: Properties of Electrons
Topic: Constructive vs Destructive
Replies: 6
Views: 41

Re: Constructive vs Destructive

If there is either a trough-trough or a peak-peak interaction then it is constructive, but if it is trough-peak then it is a destructive interaction.
by Tobie Jessup Section 3D
Sun Nov 01, 2020 10:55 pm
Forum: Properties of Electrons
Topic: question about diffraction
Replies: 4
Views: 26

Re: question about diffraction

If the electrons were solely acting as particles, they would pass through the two slits in the board and make clear lines, but since they act like waves we see the pattern in the picture where that are points of overlapping waves.
by Tobie Jessup Section 3D
Sun Nov 01, 2020 10:53 pm
Forum: Properties of Electrons
Topic: Rydberg's Equation
Replies: 6
Views: 27

Re: Rydberg's Equation

I remember that n1 is alway the lower energy shell because having a lower value in n1 ensures that the answer that comes out of the equation will be positive, whereas if the larger number was first the number would come out negative. Not a very scientific way to explain but an easy way that I've bee...
by Tobie Jessup Section 3D
Sun Oct 25, 2020 11:14 pm
Forum: Properties of Light
Topic: Midterm
Replies: 42
Views: 368

Re: Midterm

Do you guys know if the midterm is all multiple choice?
by Tobie Jessup Section 3D
Sun Oct 25, 2020 11:13 pm
Forum: Properties of Light
Topic: How are you guys studying for the midterm?
Replies: 19
Views: 55

Re: How are you guys studying for the midterm?

For me I usually do a lot of practice problems the days before and then make sure to also go over my notes before the test. I also think its important that we know the formulas and units within the formulas so we can check our answers/work on the test.
by Tobie Jessup Section 3D
Sun Oct 25, 2020 11:12 pm
Forum: Properties of Light
Topic: Units for wavelength/frequency
Replies: 18
Views: 84

Re: Units for wavelength/frequency

The units of wavelength is meters (m) and the unit for frequency is Hertz (Hz), which is s^-1. Nano meters aren't very commonly used and it is also important to keep track of these units in these calculations, like understanding that Hz is really s^-1.
by Tobie Jessup Section 3D
Sun Oct 25, 2020 11:09 pm
Forum: Properties of Light
Topic: Is c always the speed of light?
Replies: 70
Views: 236

Re: Is c always the speed of light?

From what I understand, the speed of light is always said to be constant c. c is also the fastest speed, so it is telling if an answer to a question is more than the speed of light because it must be incorrect.
by Tobie Jessup Section 3D
Sun Oct 25, 2020 11:06 pm
Forum: Administrative Questions and Class Announcements
Topic: Where can I buy a webcam for a reasonable price?
Replies: 60
Views: 923

Re: Where can I buy a webcam for a reasonable price?

Is using our phone or another device for the midterm okay instead of a webcam?
by Tobie Jessup Section 3D
Sun Oct 18, 2020 7:29 pm
Forum: General Science Questions
Topic: Sapling Homework
Replies: 14
Views: 136

Re: Sapling Homework

Dr. Lavelle sent an email detailing the update to the homework change. It is now due week 4 and includes weeks 2,3, and 4 but the material from week 4 will not be on the midterm.
by Tobie Jessup Section 3D
Sun Oct 18, 2020 7:26 pm
Forum: General Science Questions
Topic: Sig Figs
Replies: 14
Views: 70

Re: Sig Figs

In high school I was taught to use 3 sig figs but I think a good rule of thumb is to avoid rounding util the end and use the same amount of sig figs that is used in the problem.
by Tobie Jessup Section 3D
Sun Oct 18, 2020 7:15 pm
Forum: General Science Questions
Topic: Kelvin
Replies: 8
Views: 53

Re: Kelvin

Kelvin itself is the unit, unlike Celsius and Fahrenheit.
by Tobie Jessup Section 3D
Sun Oct 18, 2020 7:13 pm
Forum: General Science Questions
Topic: Writing Formulas
Replies: 10
Views: 50

Re: Writing Formulas

I dot think it hurts to memorize some, but from what I know formulas will be given to us!
by Tobie Jessup Section 3D
Sun Oct 18, 2020 7:08 pm
Forum: General Science Questions
Topic: Rusty on High School Chem [ENDORSED]
Replies: 200
Views: 141258

Re: Rusty on High School Chem [ENDORSED]

I also have not taken chemistry in 4 years now so these responses were very helpful! It is definitely frustrating relearning concepts that I have forgotten but Dr. Lavelle has definitely given us a huge amount of resources to help us.
by Tobie Jessup Section 3D
Sun Oct 11, 2020 10:12 pm
Forum: Balancing Chemical Reactions
Topic: Order of Balancing Rxns
Replies: 23
Views: 102

Re: Order of Balancing Rxns

It definitely helps to start with the element that occurs the least and work from there! sometimes there can be a bit of tail and error to balance each side of the equation.
by Tobie Jessup Section 3D
Sun Oct 11, 2020 10:10 pm
Forum: Molarity, Solutions, Dilutions
Topic: Sapling HW Number 7
Replies: 12
Views: 118

Re: Sapling HW Number 7

Since the solution is solely CaCl and water, you know that the solution is 36% CaCl by mass (given) and therefore 64% water by mass. The total mass is 855.1 g you can multiply the total mass by .36 to find the mass of CaCl in the solution and .64 to find the mass of water in the solution
by Tobie Jessup Section 3D
Sun Oct 11, 2020 10:07 pm
Forum: Empirical & Molecular Formulas
Topic: Sapling Homework 1 Q#9
Replies: 21
Views: 246

Re: Sapling Homework 1 Q#9

I also had trouble determining how to approach this question, but this thread was very helpful. I think it was really key to understand how to use the grams of products given to find the mass and moles of C, H, and O. From there, the rest of the problem was generally straight forward!
by Tobie Jessup Section 3D
Sun Oct 11, 2020 9:53 pm
Forum: Significant Figures
Topic: Sapling HW #4
Replies: 31
Views: 241

Re: Sapling HW #4

I also had trouble with this question since I hadn't worked with determining sig figs in a super long time but something that really helped me was understanding the differences between leading and trailing zeros, like some of our peers said above^
by Tobie Jessup Section 3D
Sun Oct 11, 2020 9:51 pm
Forum: Limiting Reactant Calculations
Topic: Sapling Homework Week 1 Q10
Replies: 6
Views: 127

Re: Sapling Homework Week 1 Q10

I was also very confused on how to approach this question at first, a key issue I had was recognizing the 1:1 ratio of product to reactant to determine the mols of product and therefore the theoretical yield. So thanks to this thread I was able to solve this problem!

Go to advanced search